The manufacture of window fittings and building facades frequently uses walls constituted by two panes of glass, mounted parallel to one another and brought together on a frame and creating a space filled with air between them; such walls are commonly known as “double glazing”.
The use of such walls, introduced primarily to obtain insulation, both thermal and acoustic, between the interior and exterior environments, often prove somewhat inefficient, especially in applications in which the quality of the surface of the glass is relatively high (for example, in the case of entire facades made of glass).
In particular, during the winter, when the interior is artificially heated, double-glazed walls of the known type cause excessive heat dispersion towards the exterior, thus entailing high energy consumption associated to the so-called “cold wall” effect, that can be experienced in the vicinity of the windows, which can be bothersome when the temperature outside is very low (effect often accompanied by unpleasant condensation deposits of the water vapor present inside).
During the summer, interiors are usually kept cool by air conditioning systems, at a temperature often decidedly lower than that outside: it is therefore necessary to prevent the often considerable amounts of energy required to maintain the interior at an optimal temperature for the people inside from being wasted due to diffusion of solar heat through the windows or building facades in glass.